This invention relates generally to vision systems, particularly for vehicles which provide a vehicle operator with wide angle scenic information of an area immediately around the vehicle. While the invention is illustrated in a rear-view vision system, it may be applied to other viewing directions, as well as to non-vehicular applications.
A long felt need in the art of vehicle vision systems, such as rear-view systems, has been to provide an operator of a vehicle with wide angle scenic information of an area around the vehicle, such as directly rearward of the vehicle, when the vehicle is traveling in reverse. Neither interior rear-view mirrors nor side exterior mirrors allow for visibility of the area immediately rearward of the vehicle's bumper, which is the information most critical to the vehicle operator when backing up. Therefore, various camera-based rear view vision systems have been proposed to provide visibility of this blind spot.
Various camera-based rear vision systems for vehicles backing up have been proposed. In one form of these systems, a camera with a conventional, standard lens is located on the rearward portion of the vehicle to provide a view of the area behind the vehicle. However, standard lenses fail to capture a wide angle view of the area, thus failing to provide the vehicle operator with an image of the entire critical area directly rearward of the vehicle.
In order to provide a wider angle view of the rearward area, a wide angle lens system may be used with the camera to capture the critical area. However, because the wide angle lens elements are typically precision optics, not only is the initial cost to manufacture and implement them very high, but so is the cost to replace them, should they be damaged or broken on the vehicle in the vulnerable area in which they are typically located.
Another difficulty with the proposed multi-element glass lens and camera systems is that they are difficult to package within the small area available at the rearward portion of the vehicle. These systems may comprise ten or more precision optic lens elements and are thus assembled as a long, horizontally oriented cylindrical column, which is then positioned within the trunk lid or a rear panel of the vehicle. This results in the camera system protruding substantially forwardly into the trunk space. Generally, it is desirable to minimize intrusion into the trunk space, such that the overall trunk space is maximized. This is desirable not only because trunk space is considered valuable to consumers, but also because consumers tend to over-pack their trunk spaces, and then force the trunk lid closed, which may result in damage to any components trapped between the packed items and the trunk lid. This is an even greater concern with the proposed multi-element glass lens systems, since the many optic elements may be fragile and thus prone to breaking. In a van, pick-up truck or the like, the long, cylindrical column of these camera systems would extend forward into an open space, and be more prone to damage.